Preparation for the next patch:

In the slow-path of perform_atomic_semop(), store a pointer to the
operation that caused the operation to block.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Right now, perform_atomic_semop gets the content of sem_queue as
individual fields.  Changes that, instead pass a pointer to sem_queue.

This is a preparation for the next patch: it uses sem_queue to store the
reason why a task must sleep.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

count_semzcnt and count_semncnt are more of less identical.  The patch
creates a single function that either counts the number of tasks waiting
for zero or waiting due to a decrease operation.

Compared to the initial version, the BUG_ONs were removed.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

GETZCNT is supposed to return the number of threads that wait until a
semaphore value becomes 0.

The current implementation overlooks complex operations that contain
both wait-for-zero operation and operations that alter at least one
semaphore.

The patch fixes that.  It's intentionally copy&paste, this will be
cleaned up in the next patch.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The need for volatile is not obvious, document it.
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Nothing big and no logical changes, just get rid of some redundant
function declarations.  Move msg_[init/exit]_ns down the end of the
file.
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Call __set_current_state() instead of assigning the new state directly.
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Signed-off-by: NManfred Spraul <manfred@colorfullif.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is useful in the future and allows users to better understand the
reasoning behind the changes.

Also use UL as we're dealing with it anyways.
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

System V shared memory

a) can be abused to trigger out-of-memory conditions and the standard
   measures against out-of-memory do not work:

    - it is not possible to use setrlimit to limit the size of shm segments.

    - segments can exist without association with any processes, thus
      the oom-killer is unable to free that memory.

b) is typically used for shared information - today often multiple GB.
   (e.g. database shared buffers)

The current default is a maximum segment size of 32 MB and a maximum
total size of 8 GB.  This is often too much for a) and not enough for
b), which means that lots of users must change the defaults.

This patch increases the default limits (nearly) to the maximum, which
is perfect for case b).  The defaults are used after boot and as the
initial value for each new namespace.

Admins/distros that need a protection against a) should reduce the
limits and/or enable shm_rmid_forced.

Unix has historically required setting these limits for shared memory,
and Linux inherited such behavior.  The consequence of this is added
complexity for users and administrators.  One very common example are
Database setup/installation documents and scripts, where users must
manually calculate the values for these limits.  This also requires
(some) knowledge of how the underlying memory management works, thus
causing, in many occasions, the limits to just be flat out wrong.
Disabling these limits sooner could have saved companies a lot of time,
headaches and money for support.  But it's never too late, simplify
users life now.

Further notes:
- The patch only changes default, overrides behave as before:
        # sysctl kernel.shmall=33554432
  would recreate the previous limit for SHMMAX (for the current namespace).

- Disabling sysv shm allocation is possible with:
        # sysctl kernel.shmall=0
  (not a new feature, also per-namespace)

- The limits are intentionally set to a value slightly less than ULONG_MAX,
  to avoid triggering overflows in user space apps.
  [not unreasonable, see http://marc.info/?l=linux-mm&m=139638334330127]
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Signed-off-by: NDavidlohr Bueso <davidlohr@hp.com>
Reported-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

SHMMAX is the upper limit for the size of a shared memory segment, counted
in bytes.  The actual allocation is that size, rounded up to the next full
page.

Add a check that prevents the creation of segments where the rounded up
size causes an integer overflow.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Acked-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

shm_tot counts the total number of pages used by shm segments.

If SHMALL is ULONG_MAX (or nearly ULONG_MAX), then the number can
overflow.  Subsequent calls to shmctl(,SHM_INFO,) would return wrong
values for shm_tot.

The patch adds a detection for overflows.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Acked-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The increase of SHMMAX/SHMALL is a 4 patch series.

The change itself is trivial, the only problem are interger overflows.
The overflows are not new, but if we make huge values the default, then
the code should be free from overflows.

SHMMAX:

- shmmem_file_setup places a hard limit on the segment size:
  MAX_LFS_FILESIZE.

  On 32-bit, the limit is > 1 TB, i.e. 4 GB-1 byte segments are
  possible. Rounded up to full pages the actual allocated size
  is 0. --> must be fixed, patch 3

- shmat:
  - find_vma_intersection does not handle overflows properly.
    --> must be fixed, patch 1

  - the rest is fine, do_mmap_pgoff limits mappings to TASK_SIZE
    and checks for overflows (i.e.: map 2 GB, starting from
    addr=2.5GB fails).

SHMALL:
- after creating 8192 segments size (1L<<63)-1, shm_tot overflows and
  returns 0.  --> must be fixed, patch 2.

Userspace:
- Obviously, there could be overflows in userspace. There is nothing
  we can do, only use values smaller than ULONG_MAX.
  I ended with "ULONG_MAX - 1L<<24":

  - TASK_SIZE cannot be used because it is the size of the current
    task. Could be 4G if it's a 32-bit task on a 64-bit kernel.

  - The maximum size is not standardized across archs:
    I found TASK_MAX_SIZE, TASK_SIZE_MAX and TASK_SIZE_64.

  - Just in case some arch revives a 4G/4G split, nearly
    ULONG_MAX is a valid segment size.

  - Using "0" as a magic value for infinity is even worse, because
    right now 0 means 0, i.e. fail all allocations.

This patch (of 4):

find_vma_intersection() does not work as intended if addr+size overflows.
The patch adds a manual check before the call to find_vma_intersection.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Acked-by: NDavidlohr Bueso <davidlohr@hp.com>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

trailing whitespace
Signed-off-by: NPaul McQuade <paulmcquad@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
Use #include <linux/types.h> instead of <asm/types.h>
Signed-off-by: NPaul McQuade <paulmcquad@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no need to recreate the very same ipc_ops structure on every
kernel entry for msgget/semget/shmget.  Just declare it static and be
done with it.  While at it, constify it as we don't modify the structure
at runtime.

Found in the PaX patch, written by the PaX Team.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 9ba4bcb6 ("initramfs: read CONFIG_RD_ variables for initramfs
compression") removed the users of the various INITRAMFS_COMPRESSION_*
Kconfig symbols.  So since v3.13 the entire "Built-in initramfs
compression mode" choice is a set of knobs connected to nothing.  The
entire choice can safely be removed.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Cc: P J P <ppandit@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Also convert spaces to tabs (checkpatch warnings) if (!dentry) KERN_NOTICE
converted to pr_err (like if (!inode) error process)

[akpm@linux-foundation.org: use KBUILD_MODNAME, per Joe]
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Joe Perches <joe@perches.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Also add pr_fmt in internal.h
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- Define pr_fmt in plateform.c and ram_core.c for global prefix.

- Coalesce format fragments.

- Separate format/arguments on lines > 80 characters.

Note: Some pr_foo() were initially declared without prefix and therefore
this could break existing log analyzer.

[akpm@linux-foundation.org: missed a couple of prefix removals]
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Joe Perches <joe@perches.com>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

schedstr, sleepstr and kvmstr are only used in strcmp & strlen
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- Remove AFFS: prefix (defined in pr_fmt)

- Use __func__

- Separate format/arguments on lines > 80 characters.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

-All printk(KERN_foo converted to pr_foo()

-Default printk converted to pr_warn()

-Add pr_fmt to affs.h
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- affs_do_readpage_ofs is always called with from = 0 ie reading from
  page->index

- File parameter is never used
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When running sparse over drivers/media/v4l2-core/v4l2-ioctl.c I get these
errors:

  drivers/media/v4l2-core/v4l2-ioctl.c:2043:9: error: bad integer constant expression
  drivers/media/v4l2-core/v4l2-ioctl.c:2044:9: error: bad integer constant expression
  drivers/media/v4l2-core/v4l2-ioctl.c:2045:9: error: bad integer constant expression
  drivers/media/v4l2-core/v4l2-ioctl.c:2046:9: error: bad integer constant expression

etc.

The root cause of that turns out to be in include/asm-generic/ioctl.h:

#include <uapi/asm-generic/ioctl.h>

/* provoke compile error for invalid uses of size argument */
extern unsigned int __invalid_size_argument_for_IOC;
#define _IOC_TYPECHECK(t) \
        ((sizeof(t) == sizeof(t[1]) && \
          sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
          sizeof(t) : __invalid_size_argument_for_IOC)

If it is defined as this (as is already done if __KERNEL__ is not defined):

  #define _IOC_TYPECHECK(t) (sizeof(t))

then all is well with the world.

This patch allows sparse to work correctly.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

-uid->gid
-split some function declarations
-if/then/else warning
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds several behavioral tests to sysctl string and number writing
to detect unexpected cases that behaved differently when the sysctl
kernel.sysctl_writes_strict != 1.

[ original ]
    root@localhost:~# make test_num
    == Testing sysctl behavior against /proc/sys/kernel/domainname ==
    Writing test file ... ok
    Checking sysctl is not set to test value ... ok
    Writing sysctl from shell ... ok
    Resetting sysctl to original value ... ok
    Writing entire sysctl in single write ... ok
    Writing middle of sysctl after synchronized seek ... FAIL
    Writing beyond end of sysctl ... FAIL
    Writing sysctl with multiple long writes ... FAIL
    Writing entire sysctl in short writes ... FAIL
    Writing middle of sysctl after unsynchronized seek ... ok
    Checking sysctl maxlen is at least 65 ... ok
    Checking sysctl keeps original string on overflow append ... FAIL
    Checking sysctl stays NULL terminated on write ... ok
    Checking sysctl stays NULL terminated on overwrite ... ok
    make: *** [test_num] Error 1
    root@localhost:~# make test_string
    == Testing sysctl behavior against /proc/sys/vm/swappiness ==
    Writing test file ... ok
    Checking sysctl is not set to test value ... ok
    Writing sysctl from shell ... ok
    Resetting sysctl to original value ... ok
    Writing entire sysctl in single write ... ok
    Writing middle of sysctl after synchronized seek ... FAIL
    Writing beyond end of sysctl ... FAIL
    Writing sysctl with multiple long writes ... ok
    make: *** [test_string] Error 1

[ with CONFIG_PROC_SYSCTL_STRICT_WRITES ]
    root@localhost:~# make run_tests
    == Testing sysctl behavior against /proc/sys/kernel/domainname ==
    Writing test file ... ok
    Checking sysctl is not set to test value ... ok
    Writing sysctl from shell ... ok
    Resetting sysctl to original value ... ok
    Writing entire sysctl in single write ... ok
    Writing middle of sysctl after synchronized seek ... ok
    Writing beyond end of sysctl ... ok
    Writing sysctl with multiple long writes ... ok
    Writing entire sysctl in short writes ... ok
    Writing middle of sysctl after unsynchronized seek ... ok
    Checking sysctl maxlen is at least 65 ... ok
    Checking sysctl keeps original string on overflow append ... ok
    Checking sysctl stays NULL terminated on write ... ok
    Checking sysctl stays NULL terminated on overwrite ... ok
    == Testing sysctl behavior against /proc/sys/vm/swappiness ==
    Writing test file ... ok
    Checking sysctl is not set to test value ... ok
    Writing sysctl from shell ... ok
    Resetting sysctl to original value ... ok
    Writing entire sysctl in single write ... ok
    Writing middle of sysctl after synchronized seek ... ok
    Writing beyond end of sysctl ... ok
    Writing sysctl with multiple long writes ... ok
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When writing to a sysctl string, each write, regardless of VFS position,
begins writing the string from the start.  This means the contents of
the last write to the sysctl controls the string contents instead of the
first:

  open("/proc/sys/kernel/modprobe", O_WRONLY)   = 1
  write(1, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"..., 4096) = 4096
  write(1, "/bin/true", 9)                = 9
  close(1)                                = 0

  $ cat /proc/sys/kernel/modprobe
  /bin/true

Expected behaviour would be to have the sysctl be "AAAA..." capped at
maxlen (in this case KMOD_PATH_LEN: 256), instead of truncating to the
contents of the second write.  Similarly, multiple short writes would
not append to the sysctl.

The old behavior is unlike regular POSIX files enough that doing audits
of software that interact with sysctls can end up in unexpected or
dangerous situations.  For example, "as long as the input starts with a
trusted path" turns out to be an insufficient filter, as what must also
happen is for the input to be entirely contained in a single write
syscall -- not a common consideration, especially for high level tools.

This provides kernel.sysctl_writes_strict as a way to make this behavior
act in a less surprising manner for strings, and disallows non-zero file
position when writing numeric sysctls (similar to what is already done
when reading from non-zero file positions).  For now, the default (0) is
to warn about non-zero file position use, but retain the legacy
behavior.  Setting this to -1 disables the warning, and setting this to
1 enables the file position respecting behavior.

[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: move misplaced hunk, per Randy]
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Consolidate buffer length checking with new-line/end-of-line checking.
Additionally, instead of reading user memory twice, just do the
assignment during the loop.

This change doesn't affect the potential races here.  It was already
possible to read a sysctl that was in the middle of a write.  In both
cases, the string will always be NULL terminated.  The pre-existing race
remains a problem to be solved.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When writing to a sysctl string, each write, regardless of VFS position,
began writing the string from the start.  This meant the contents of the
last write to the sysctl controlled the string contents instead of the
first.

This misbehavior was featured in an exploit against Chrome OS.  While
it's not in itself a vulnerability, it's a weirdness that isn't on the
mind of most auditors: "This filter looks correct, the first line
written would not be meaningful to sysctl" doesn't apply here, since the
size of the write and the contents of the final write are what matter
when writing to sysctls.

This adds the sysctl kernel.sysctl_writes_strict to control the write
behavior.  The default (0) reports when VFS position is non-0 on a
write, but retains legacy behavior, -1 disables the warning, and 1
enables the position-respecting behavior.

The long-term plan here is to wait for userspace to be fixed in response
to the new warning and to then switch the default kernel behavior to the
new position-respecting behavior.

This patch (of 4):

The char buffer arguments are needlessly cast in weird places.  Clean it
up so things are easier to read.
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As result of deprecation of MSI-X/MSI enablement functions
pci_enable_msix() and pci_enable_msi_block() all drivers using these two
interfaces need to be updated to use the new pci_enable_msi_range() or
pci_enable_msi_exact() and pci_enable_msix_range() or
pci_enable_msix_exact() interfaces.

The patch has no runtime effect.
Signed-off-by: NAlexander Gordeev <agordeev@redhat.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_layer->layer is always accessed in read path, move it in the front.

idr_layer->bitmap is moved on the bottom.  And rcu_head shares with
bitmap due to they do not be accessed at the same time.

idr->id_free/id_free_cnt/lock are free list fields, and moved to the
bottom.  They will be removed in near future.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If "idr->hint == p" is true, it also implies "idr->hint" is true(not NULL).
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After idr subsystem is changed to RCU-awared, the free layer will not go
to the free list.  The free list will not be filled up when
idr_remove().  So we don't need to shink it too.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When the smaller id is not found, idr_replace() returns -ENOENT.  But
when the id is bigger enough, idr_replace() returns -EINVAL, actually
there is no difference between these two kinds of ids.

These are all unallocated id, the return values of the idr_replace() for
these ids should be the same: -ENOENT.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the ida has at least one existing id, and when an unallocated ID
which meets a certain condition is passed to the ida_remove(), the
system will crash because it hits NULL pointer dereference.

The condition is that the unallocated ID shares the same lowest idr
layer with the existing ID, but the idr slot would be different if the
unallocated ID were to be allocated.

In this case the matching idr slot for the unallocated_id is NULL,
causing @bitmap to be NULL which the function dereferences without
checking crashing the kernel.

See the test code:

  static void test3(void)
  {
        int id;
        DEFINE_IDA(test_ida);

        printk(KERN_INFO "Start test3\n");
        if (ida_pre_get(&test_ida, GFP_KERNEL) < 0) return;
        if (ida_get_new(&test_ida,  &id) < 0) return;
        ida_remove(&test_ida, 4000); /* bug: null deference here */
        printk(KERN_INFO "End of test3\n");
  }

It happens only when the caller tries to free an unallocated ID which is
the caller's fault.  It is not a bug.  But it is better to add the
proper check and complain rather than crashing the kernel.

[tj@kernel.org: updated patch description]
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If unallocated_id = (ANY * idr_max(idp->layers) + existing_id) is passed
to idr_remove().  The existing_id will be removed unexpectedly.

The following test shows this unexpected id-removal:

  static void test4(void)
  {
        int id;
        DEFINE_IDR(test_idr);

        printk(KERN_INFO "Start test4\n");
        id = idr_alloc(&test_idr, (void *)1, 42, 43, GFP_KERNEL);
        BUG_ON(id != 42);
        idr_remove(&test_idr, 42 + IDR_SIZE);
        TEST_BUG_ON(idr_find(&test_idr, 42) != (void *)1);
        idr_destroy(&test_idr);
        printk(KERN_INFO "End of test4\n");
  }

ida_remove() shares the similar problem.

It happens only when the caller tries to free an unallocated ID which is
the caller's fault.  It is not a bug.  But it is better to add the
proper check and complain rather than removing an existing_id silently.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

idr_replace() open-codes the logic to calculate the maximum valid ID
given the height of the idr tree; unfortunately, the open-coded logic
doesn't account for the fact that the top layer may have unused slots
and over-shifts the limit to zero when the tree is at its maximum
height.

The following test code shows it fails to replace the value for
id=((1<<27)+42):

  static void test5(void)
  {
        int id;
        DEFINE_IDR(test_idr);
  #define TEST5_START ((1<<27)+42) /* use the highest layer */

        printk(KERN_INFO "Start test5\n");
        id = idr_alloc(&test_idr, (void *)1, TEST5_START, 0, GFP_KERNEL);
        BUG_ON(id != TEST5_START);
        TEST_BUG_ON(idr_replace(&test_idr, (void *)2, TEST5_START) != (void *)1);
        idr_destroy(&test_idr);
        printk(KERN_INFO "End of test5\n");
  }

Fix the bug by using idr_max() which correctly takes into account the
maximum allowed shift.

sub_alloc() shares the same problem and may incorrectly fail with
-EAGAIN; however, this bug doesn't affect correct operation because
idr_get_empty_slot(), which already uses idr_max(), retries with the
increased @id in such cases.

[tj@kernel.org: Updated patch description.]
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

+ some pr_warning -> pr_warn and checkpatch warning fixes
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>